Backbone resonance assignments of the homotetrameric (48 kD) copper sensor CsoR from Geobacillus thermodenitrificans in the apo- and Cu(I)-bound states: insights into copper-mediated allostery

Prokaryotes are highly susceptible to exogenous copper and employ metalloregulatory proteins to control the intracellular concentration. CsoR (copper-sensitive operon repressor) is one such protein that represses transcription of a Cu(I)-effluxing ATPase in its apo form. Cu(I)-binding leads to transcriptional derepression and cellular copper resistance. Herein, we present substantially complete backbone (H-N, N, C', C alpha, C beta) resonance assignments of tetrameric (48 kD) Geobacillus thermodenitrificans (Gt) CsoR in its apo- and Cu(I)-saturated states. These data provide the first spectroscopic evidence that Cu(I)-binding induces an interruption in the long alpha 2 helix of CsoR.